Ubuntu 9.04 XBMC Nvidia ion Digital audio problem

i bought myself i Point of view nvidia ion board and built up an HTPC,
installed ubuntu since it seemed like the best choice with hardware decoding etc
but i cant get digital audio to work, neither with hdmi or toslink,
tried searching the web but didnt find much i could use.

So any help to make Digital audio work is greatly appriciated

the sound problem is both in xbmc and ubuntu,
and i see that i probably will work in xbmc live, but i want to use the htpc for
more than just xbmc so i went with full ubuntu install.